Vehicles offer the promise of powered transportation through the use of electric motors while producing few or no emissions. Some electric vehicles are powered by electric motors only and rely solely on the energy stored in an on-board battery pack. Other electric vehicles are hybrids, and include an internal combustion engine, which may, for example, be used to assist the electric motor in driving the wheels (a parallel hybrid), or which may, for example, be used solely to charge the on-board battery pack, thereby extending the operating range of the vehicle (a series hybrid). In some vehicles, there is a single, centrally-positioned electric motor that powers one or more of the vehicle wheels, and in other vehicles, one or more of the wheels have an electric motor positioned at each driven wheel.
While currently proposed and existing vehicles are advantageous in some respects over internal-combustion engine powered vehicles, there are problems that are associated with some electric vehicles. A particular problem is that their range is typically relatively short as compared to internal combustion engine-powered vehicles. This is particularly true for battery electric vehicles that are not equipped with range extender engines. A reason for this limitation is the weight and cost of the battery packs used to store energy for the operation of such vehicles. It would be beneficial to provide technology that improves the efficiency with which power is used in the operation of the vehicle, so as to improve the range of such vehicles.